Most direct possible route = 9000 miles, more or less. You do the math.
There's no mystery about it: get a map of North America and choose a nice, direct route from the several available. Stick to interstates as much as possible before arcing north to pick up the Alcan. You'll spend a lot of time riding, some of the rest doing maintenance and repairs, and have little or no time remaining to stop, deviate or enjoy. Plus: the direct routes are often not the most scenic, and you'll be in such a hurry you'll be following the same route (basically) homeward. On the plus side, it's all paved save the last little bit, and services will all be open in July.
Nothing wrong with that, but to me it doesn't sound like a whole lot of fun. If it appeals to you, by all means have at it: you won't be the only one.
Hope that's helpful. If that's not what you're asking about, maybe post again with some specific questions.